Spark-plug



D. S. SHORT.

SPARK PLUG.

v APPLICATION FILED Nov.26,T9|T.

Patented Apr.` 6, 1920.

L AMY WM I9. wm.

WITNESSES ATTORNEY UNITED srrn DAVID SfSI-IORT, 0F INDIANAPOLIS, INDIANA.

SPARK-PLUG.

Specification of Letters Patent.

Patented Apr. 6, 1920.

Application filed November 26, 1917. Serial No. 204,023.

To alt whomj it may Concern.'

Be it known that I, DAVID S. SHORT, a citizen of the United States, residing at Indianapolis, in the county of Marion and State of Indiana, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specilic'ation.

This invention is a spark plug more particularly adapted for use in firing the explosive charges of an internal combustion engine, wherein suitable terminals are formed forI the passage of a spark across a gap, and within the body of the insulator an adjustable and secondary spark gap is provided.

One object of the invention is to provide a spark plug having the usual insulated terminal that is connected to one section of the insulated electrode, and provided for adj ustment with and to the usual section of the electrode. Y

Another object of the invention is to provide a spark plug having an insulator formed in parts, the lower one of which is adapted to coperate with the lower section of the electrode and be adjustably held said section being provided at one end with rounded or tapered points to form spark points.

A further objectof the invention is to provide a spark plug with an electrode formed of section, each one of which is adjustable relative to the other, and one of the sections is further adjustable relative to the cylindrical and provided at one end with a flange, and a recess therein concentric to the bore, the opposite end of said portion of the insulator being provided with. threaded engaging means, a sub-divided electrode disposed within the insulator, one section of which is disposed within one portion of the insulator, each section of said electrode being provided with screw threads to cooperate with suitable nuts for providing separate adjustment relative to each other assembly will be described and illustrated i'n the accompanying drawings, in which z- Figure 1 is an elevation of the assembled spark plug,

Fig. 2 is a vertical sectional view of the plug shown in Fig. 1, and j Fig. 3 is a sectional View on the line 3-3 Aor' Fig. 2.

In the preferred embodiment about to be described the spark plug is provided .with the usual hexagonal metallic threaded shell 5 that is provided internally with a bore 6 having .a shouldered'portion 7 where the bore is of greater diameter and forming threads within these larger diametered portions ot the bore. The threads9 are frmed adjacent one end so that the plug may be screwed into the walls of an internal combustion engine.

At the lower end of the shell 5 there is provided the usual stationary elect'ode'l() that may be L-shaped as shown. The free.

end of the electrode 10 is adapted to form a spark point. To coperate with the threads 8 the threaded locking. nut 11 is employed. This nut may be also hexagonal so that it may bc engaged by a wrench when so desired. The shell 5 may be lalso engaged with a wrench for screwing into and outv of face of which lies flush with the end -of the insulator 12.

The other portion 13(0f the insulator is lalso provided with a fiat upper surface to 55 within the insulator, one of said nuts being engage with the flat under surface with the disposed within the concentric recess, means upper portion 12. The portion 13 is prO- vided with a body portion having a rounded llange 19 that is adapted to be seated on the rounded shoulder' 7. The portion 13 is also provided with a downwardly projecting petticoat 20. The petticoat is provided with allongitudinal bore `21V of larger diameter than the longitudinal bore 22 passing through the body portion. To cooperate with the nut Y18 there is a section 23 that forms one portion or section of the electrode. vAs shown the section 23y is provided with the tapered ends 24C and 25. The upper portion 'of the section 23 is provided with The section 28 of the electrode is prefer-- ably threaded a's indicated at 29 throughout the greater portion'of its length. It is further rovided with a tapered point 3() that is ac apted to coperate with the tapered point 25. The threads 29 are tapered to co-v operate with the threaded means 15. The insulator portion 12 has in engagement at one end a lock washer 31 that also cooperates with the threaded section of the electrode 28.

Coperating with the washer 31 there is a thumbl nut 32 that also runs on the v'threaded electrode 28. The upper end of the electrode 28 may be slotted as indicated at 33 so that a suitable tooll may be engaged to rotate the section and thus screw it in `and out. It will be seen from the several points of construction that the sections 23 and 28 .may be adjusted relative to each Iother and Y with respect to the stationary electrode 10.

The points 25 and 30 may also serve as a secondaryv spark gap.

What I claim is:

1. A spark plug, comprising a metallic shell having a shoulder formed interiorly thereof, a sectional insulator core, the lower section of which is provided at the top with an exterior flange adapted to be seated on the interior shoulder of the shell, the upper section of said core having a flange at its lower edge adapted to `rest upon the flange portion of said lower section, the' bore eX- tending through the sectional insulator, the lower end being of 'an enlarged diameter and a sectional electrode adjustably mounted within said'bore, one section of said electrode positioned to depend within the bore of the upper insulator section, the other electrode section adjustably disposed within the enlarged bore of the lower insulator section and adjusting means within the larger bore for projecting the lower electrode partially into the bore of the upper insulator section, to create a secondary spark gap with respect to the other electrode .section and within the bore of the upper insulator.

2. A spark plug comprising a metallic shell having a shoulder formed interiorly thereof, a sectional insulator core, the lower section having its top flange adapted to be seated upon the interior shoulder of the shell, the other section having a flange 'at its lower edge adapted to rest upon the flange of the lower section, the bore extending through the sectional insulator core, a sectional electrode adjustably mounted in said bore and threaded adjusting means carried by said upper insulator lsect-ion for enand projecting the electrode there-l sgine 1n, adjusting means provided 1n the lower insulator section for gripping an electrode section supported therein, said means gripping andsupporting said electrode section -within the bore of said insulator.v

In testimony whereof I aliix my signature y in presence of'two witnesses.

DAVID S. SHORT.

Witnesses:

, WALLIAH. JENNINGS,

MoNTE C. Fiscus. 

